The role of interception in the water budget of spruce stands in the Eastern Ore Mountains/Germany

• Published in: Physics and chemistry of the earth. Part B, Hydrology, oceans and atmosphere Hydrology, oceans and atmosphere, 1999-01, Vol.24 (7), p.809-812
• Main Authors: Zimmermann, L., Frühauf, C., Bernhofer, Ch
• Format: Article
• Language: English
• ISSN: 1464-1909
• DOI: 10.1016/S1464-1909(99)00085-4

In the Eastern Ore Mountains large areas situated at the ridge are deforested mainly due to high levels of atmospheric sulphur dioxide. For the quantification of element budgets the water budget of small forested experimental watersheds is recorded, one situated in the upper, the other in the lower mountains. Interception is a major part of forest evapotranspiration in humid climates due to their low aerodynamic resistances. Interception was measured representatively at two spruce sites. It made up 51% of open-field precipitation in summer at the lower elevation site but only 28% at the higher site. The absolute figures of interception and its portion of eddy-covariance-energy-balance (ECEB)-evapotranspiration (lower site: 44%, higher site: 33%) show the importance of interception for evapotranspiration. ECEB-evapotranspiration was compared to the hydrological difference of precipitation and discharge of both watersheds. The water budget of the ridge watershed showed a marked difference explained by fog interception as important additional water input for fog-rich sites, also seen by the ratios and magnitude of interception loss above. The high atmospheric coupling of spruce forests could be seen by near-equality of evapotranspiration at both sites despite an altitudinal gradient of 360 m. All these findings show the importance of proper measurement and modelling of interception for water and element budget studies of forested watersheds.